<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <script src="jquery-1.8.2.min.js"></script>
    <style>
        .sogreen {
            background-color: green;
        }
    </style>
</head>
<body>
    <div>
        <span>s1</span>
        <span>s1</span>
        <span>s1</span>
    </div>
    <div>
        <span>s1</span>
        <span>s1</span>
        <span>s1</span>
    </div>
    <div>
        <span>s1</span>
        <span>s1</span>
        <span>s1</span>
    </div>
</body>
<script>
    $(function () {
        $("div span:first-child").css("text-decoration","underline").hover(function () {
            $(this).addClass("sogreen");
        },function () {
            $(this).removeClass("sogreen");
        });
    })
</script>
</html>